1. Field of the Invention
This invention concerns a device for single-use retractable needles normally employed to give injections or to take samples on persons and animals with known methods.
The device according to the invention is fitted correctly to single-use syringes and all the needle-holder means employed in transfusions, phleboclysis and like processes.
2. Discussion of Prior Art
The device of this invention is employed mainly in the field of hospitals, doctors' surgeries, household use, etc.
The use of this type of syringe makes possible the prevention of the spread of infectious illnesses which use as their carrier of contagion blood or other liquids easily left in the used needles; in this connection we should bear in mind the methods of the spreading of various types of hepatitis and the acquired immuno-deficiency syndrome better known as AIDS.
In this case the spreading of AIDS among drug addicts should mainly be blamed on the re-use of syringes and needles still containing infected substances.
The normal syringes of the "use and throw away" type are generally employed in hospitals, doctors' surgeries, households and, above all, by drug addicts.
The advantages provided by employing single-use syringes which, when once used, cannot be re-used seem to admit of no doubt. The single-use syringes should prevent dangerous transfers of infected substances from one individual to another.
So as to prevent re-use and to ensure their non-offensive nature the single-use syringes generally comprise devices which require the willingness and care of a person who uses these devices.
The single-use syringes of the state of the art contain a device which acts when the plunger is thrust to the end of its travel with a given pressure and is held there.
Other devices require the manual clamping of a retention tooth, while others again require the screwing of protective caps, etc.
Unfortunately in many cases these devices do not work perfectly and therefore allow the syringe to be re-used.
Moreover, certain known devices do not enable the needle to be retracted and are therefore still dangerous.